Sudan's ancient cultures had their own version of the Great Australian Dream of home ownership with everyone who could afford to, building a pyramid.

The unearthing of ancient pyramids in Sudan shows greater social equality existed there 2,000 years ago than in neighbouring Eygpt, French archaeologist Professor Claude Rilly says.

Three years of digging by a French team at Sedeinga, about 200 kilometres from the Egyptian border, has unearthed 35 pyramids that emphasise the contrast between the two ancient cultures, says Rilly, director of the mission.

"Pyramids were so fashionable that everybody that could afford to build one, did," says Rilly, referring to the latter part of the Meroe kingdom, around 100-200AD.

"So we have really a kind of inflation, what I call a democratisation of the pyramid which is without equivalent anywhere, especially in Egypt."

Sudan's remote and relatively undiscovered pyramids contrast with their grander and better-known cousins to the north.

Middle-class aspirations

Egyptian pyramids, built far earlier than those in Sudan, held the tombs of kings, the royal family and nobles, but never the middle class, Rilly says.

Sudanese royalty also got their pyramids, but so did many other lesser souls, says the 53-year-old archaeologist.

"It reached layers of the population that have never been concerned by building of pyramids in Egypt," Rilly says. "This is really something new, which we didn't expect."

That is why there is such a large number. Sometimes they were built so close together, typically in a circular pattern, that there isn't enough room to squeeze between them.

The pyramids are in a necropolis of about 40 hectares that is thought to hold more than 1,000 tombs. One quarter have been found and opened so far, he says.

The structures come in various sizes, with some no more than a metre high.

All of them were made from mud brick, which wasn't expensive but still required a designer and workmen to construct.

That meant the poorest people could not afford pyramids but were buried in surrounding pits, he says speaking at his office at the Sudan National Museum.

Archaeologists began work on the site in the 1960s, focusing on a section reserved for princes. But during the past three years they discovered that more common folk had also been buried there.

Little remains, however, of Sedeinga's grandest structure. That was a temple which Egyptian Pharaoh Amenhotep III built for his wife Queen Tiye, grandmother of the boy pharaoh Tutankhamen.

It appears to have been heavily damaged during flooding perhaps around 400 or 500BC, says Rilly, whose team is funded by the French government and the University of Paris-Sorbonne.

Despite the large number of pyramids recently unearthed, little has been found inside because of plundering by tomb raiders, both ancient and modern.

But the robbers missed one tomb that has yielded "a rich site" for archaeologists - the skeleton of a child buried with four decorative collars and anklets of bronze.

The youngster was four or five years old "and we wondered why they took so much precaution to bury a young child like that", says Rilly.

Fading influence

Egypt occupied northern Sudan for about 500 years until roughly 1000BC but its cultural influence faded during the 700-year reign of the Meroe kingdom from about 350BC.

Inscriptions found in the Sedeinga tombs are in Meroitic, a phonetic writing simplified from the Egyptian.

Rilly, a world expert in the language, says Meroitic is still little understood.

But he has been able to decipher details about the social structure of families, concluding this part of the necropolis holds a lot of women.

Many were priestesses of the goddess Isis, of whom Queen Tiye was considered an incarnation.

In one of those female tombs, late last year Rilly himself made a rare discovery as he dug amid extreme heat after water entered the structure. He found a sandstone slab bearing an image of the main Egyptian god Amun.

It had originally been part of a wall in Queen Tiye's temple, and is the only entirely preserved divine figure to have been recovered.

Finds like this are rapidly advancing knowledge about the ancestors of today's Sudanese, says Rilly, who is hopeful of more revelations.

The first archaeological digs in Sudan took place only about 100 years ago, much later than in Egypt or Greece.

"The field to research is still very open and this is a science ... changing all the time. That is very stimulating," he says.